1. Field of the Invention
This invention relates to surface maintenance apparatus, and more particularly to a new and improved automatic floor cleaning machine especially adapted for wet scrubbing and vacuum drying of dirty floor surfaces.
2. Prior Art
Generally speaking, known scrubbing and vacuum drying machines usually include a liquid detergent dispenser, wet scrubbers, and a vacuum or suction device for removing the dirty liquid. Normally, whether manually or self-propelled, the transporting wheels and/or casters are located between the leading scrubbers and the trailing vacuum device. This causes problems, because the wheels and/or casters track on the slippery wet surface, making maneuvering difficult and if the vacuum device does not completely cover the wheel tracks, which often occurs on turning, the surface is not properly cleaned. Further, where the machine is of the walk-behind type, such wet slippery areas are hazardous to the operator.
In order to overcome these problems, a variety of approaches have been taken, including complicated and expensive linkages between the vacuum device and the machine frame to ensure proper coverage of the wheel tracks, and elimination of the walk-behind operation in favor of a seated operator. For example, one approach involves a separate forward propulsion unit and a trailing combined scrubber and vacuum unit, so that the transport wheels lead and thus track on a dry surface. While this approach is more effective in cleaning, the cumbersome tandem units are not readily maneuverable, and are only suitable for very large and relatively unobstructed floor areas, besides being difficult and expensive to manufacture, operate and maintain.
Even in the more recent, self-propelled floor cleaning machines of the walk-behind type, difficulty still is encountered in obtaining proper tracking of the suction device to cover the dirty wheel tracks. Likewise, problems, still occur in maneuverability, especially in backing up, because in at least one such machine, the steering handle means is incapable of turning the device while in reverse.
Furthermore, in most instances, the prior art floor cleaning machines make no provision for sweeping up a debris-laden surface prior to wet scrubbing and vacuum drying.